This is not really a medical issue but a question. Why when we fall to sleep does our body/ mind not let us fall out of bed. I recognize baby's /toddlers learn not to fall out of bed over time but since we are in a sleep state what allows the body to recognize the edge of the bed and therefore not fall out. I read an article on using bed railings for the infirmed or elderly and it just made me wonder what subconsious training is going out that keeps healthy adults from just falling out of the bed while sleeping :?